1. Field of the Invention
The present invention relates to a recording apparatus for recording an image such as a character, a figure and the like on a sheet.
2. Related Background Art
Among such recording apparatuses, there has been proposed a recording apparatus in which sheets (for example, cut sheets) are supplied one by one from a sheet stack to a recording portion where an image is recorded on the supplied sheet.
In such a recording apparatus, various kinds of arrangements between a sheet stacking portion and a recording portion have been already known.
For example, a sheet stacking portion is disposed at a rear part of an apparatus and the recording is effected at a recording portion disposed at a front part of the apparatus, or, a sheet stacking portion is disposed at a lower part of an apparatus and the recording is effected at a recording portion disposed at an upper part of the apparatus.
Further, there has been proposed a recording apparatus in which all of operations regarding the recording can be effected from one side of a frame of the recording apparatus so that any article can be rested on the recording apparatus or the recording apparatus can be housed within shelves.
Such a recording apparatus will be briefly described with reference to FIG. 9. FIG. 9 is a schematic explanatory view showing a conventional recording apparatus.
As shown, a recording apparatus 100 comprises a frame 101 within which a sheet cassette 102 in which sheets such as paper sheets are stacked, and a recording means 104 for recording an image on the sheet conveyed along a convey path 103 are housed.
Further, as shown, the convey path 103 serves to reverse the sheet in a U-turn manner within the apparatus and then to direct the sheet to the recording means 104 disposed at an upper part of the apparatus and then to discharge the recorded sheet out of the apparatus.
In FIG. 9, a side "A" shows an operation side from which the sheet cassette is mounted or dismounted, and the recorded sheet is discharged toward the side A.
As a similar arrangement, the sheet cassette 102 may be mounted or dismounted from a front side (front side of the plane of FIG. 9) of the apparatus and the recorded sheets may be discharged within the frame 101 and be removed from the front side. That is to say, the mounting and dismounting of the sheet cassette may be effected along a direction perpendicular to a sheet conveying direction within the frame 101 and the recorded sheets may be removed along such a direction.
In the recording apparatus having such a convey path, primarily, the sheet cassette is attached to the recording apparatus by fitting projections provided on the sheet cassette into recesses formed (at predetermined positions) within the apparatus.
Alternatively, the sheet cassette may be fixed by a latch lever of the recording apparatus and the sheet cassette can be dismounted by releasing the latch lever.
However, the above-mentioned conventional technique has the following disadvantages.
Since the sheet must be reversed in the U-turn manner along the small radius, it is difficult to convey a sheet having great resiliency (for example, a thick sheet).
Further, since the sheet is slidingly contacted with the convey path at the U-turn portion, the sheet is subjected to a great load, with the result that a sheet conveying force must be increased. To this end, contact pressure of a convey roller must be increased or torque of a motor must be increased.
Further, there is great possibility of jamming the sheet within the sheet convey path since the sheet is conveyed along the complicated convey path. In such a case, since the recording apparatus cannot be manipulated from various directions other than the one side, it is very difficult to perform the sheet jam treatment (removal of the jammed sheet).
The provision of the U-turn portion in the sheet convey path within the recording apparatus not only makes the entire recording apparatus bulky but also causes various problems.
However, in the conventional techniques, since conveying accuracy (positioning accuracy) was insufficient, the U-turn portion had to be provided in the sheet convey path. Namely, by providing the U-turn portion to form a convey path having a predetermined length, a sheet conveying condition achieved by various convey rollers is optimized so that an image forming position on the sheet is determined accurately.
Further, in the conventional techniques, since the sheet cassette can be dismounted during the recording operation, if the operator erroneously dismounts the sheet cassette during the recording operation, the recording operation will be interrupted.